bug(COMPONENT): MatDatePicker

### Is this a regression?

- [ ] Yes, this behavior used to work in the previous version

### The previous version in which this bug was not present was

_No response_

### Description

MatDatePicker with Signal Forms keeps on showin matDatepickerParse error if delete with keyboard a valid date un char at the time.

### Reproduction

StackBlitz link:
Steps to reproduce:
1.
2.

### Expected Behavior

Bind the control to a value.
Select or enter a valid date.
Erase the just entered date.
The forms has invalid()==false

### Actual Behavior

Bind the control to a value.
Select or enter a valid date.
Erase the just entered date.
The forms has invalid()==true

### Environment

- Angular: 22
- CDK/Material: 22
- Browser(s):
- Operating System (e.g. Windows, macOS, Ubuntu):

No source file, test, or reproduction link is provided. Start by reproducing the MatDatePicker behavior with Angular Signal Forms: bind a control, enter a valid date, and erase it one character at a time. Done means clearing the date leaves the form invalid state false without a matDatepickerParse error.

Written by the indexing model from the issue text.